Summary :
This study aimed at pointing out the supply of the positron emission tomography (PET) in the posttherapeutic follow-up of the head and neck squamous cell carcinomas and to determine the best period to perform this test. Patients and methods: twenty patients have been included in this series, 16 men and 4 women. The PET was performed between 3 and 6 months after the end of all therapy. It systematically included radiation therapy. The results of the PET have been compared with those obtained by histology. The average distance of the follow-up of the patients after the achievement of the test was 11 months. Results: they divided up according to the presence or not of an abnormal fixation on the PET imaging. Negative PETs: eigth cases. Among those, a patient showed a metastatic cervical adenopathy at five months. Positive PETs: twelve cases which can be divided into three groups according to the area of the fixation. Primary site: 8 cases, 4 of which false-positive. Cervical lymph nodes: one case. Other sites: three cases. In our series PET had a sensitivity of 87% and a specificity of 67%. Conclusion: the PET is an original imaging as it allows a corporal metabolic study at one go. It seems to be very useful in the follow-up of patients who show a head and neck squamous cell carcinoma.The best period to perform it is the third or fourth posttherapeutic month. The high sensitivity is interesting within the context of an early detection of a residual tumour, for it allows to think of a suitable therapy quicker.